I am planning to swap my 32gb mSATA SSD in Dell XPS 14 (L421x) with a 256GB mSATA SSD and would like to know the procedures to do that.
Post the swap I would also like to make the SSD the primary boot drive. A step by step guide would be really appreciated.
Some of the doubts I have is
1. Whether the Intel SRT or RAID will interfere while swapping. What precautions one needs to take.
2. How to clone the existing system from the HDD to the new SSD
First thing: be sure you buy mSATA (older technology) - not M.2 SATA (which is now common but incompatible with your system).
You'll need to disable IRST (or IRST/RAID) to use the new drive as boot. There are ways to do this without losing data, but be sure you do so BEFORE you try cloning the existing drive to the new one, if you want to do that.
I don't believe disabling RAID mode is required to use the new drive as boot since plenty of systems boot from mSATA while RAID mode is active, but what you will definitely want to disable first is the Acceleration feature inside the Rapid Storage application that is probably configured to use your 32GB SSD as a cache module for your spinning hard drive. To do that, open the Intel Rapid Storage application within Windows and find the area to configure Acceleration, then disable that feature before removing the 32GB SSD. After that, you should be able to install the new SSD and see it in Windows Disk Management just fine.
If you intend to perform a clean Windows reinstall to make your new SSD the boot device, then I agree with ejn63 that you may as well switch the SATA Operation in your BIOS over to AHCI mode rather than RAID before you perform the installation since it's simpler and you don't need RAID mode anymore anyway. If on the other hand you wish to clone your current drive to the new one, I would leave that setting alone for simplicity. In terms of performing the clone, Macrium Reflect Free is a popular choice for this purpose, it's free, and it's pretty easy to use -- and if you still need help with it, Macrium has great documentation, including this page for how to clone a disk. If you go this route, then after cloning, make sure your system is booting from the SSD by making sure it's assigned drive C after booting (if you couldn't tell based on the speed), and then you can wipe your original disk using something like the "clean" command in the Diskpart command-line tool to get rid of the various hidden Windows partitions, and then create just one big partition so you can use it as a data-only disk going forward.
Thank you for this detailed response. It is very applicable for me. I was planning to remove the 32gb msata and replace the hdd with 500gb ssd. Any problem I should look out for? I would turn off Intel Rapid Response and switch to AHCI as recommended. I plan to clone my existing windows 10 via Macrium Reflect free.